Radiator manufacture



Oct. 25, 1938. J. KARMAZIN RADIATOR MANUFACTURE Filed Jan. 25, 1935 2Sheets-Sheetl 1 Oct. 25, 1938. J. KARMAzlN RADIATOR MANUFACTURE FiledJan. 25, 1935 2 Sheets-Sheet 2 INVENTOR.

Patented Oct. 25, 19238 PATENT OFFICE RADIATOR MANUFACTU'BE JoanKarmann, nununmn,

1nd., assigner to Karmalln Engineering Company. a corporation ofMichigan Application January 25, 1935, Serial No. 3,490

l Claim.

This invention relates to radiator manufacture.

It is an object of this invention to provide a method of manufacture oftubing and radiators in which the tubing or radiator may be assembledand bonded together in a fluid-tight manner without undue loss ofbonding material.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings:

Fig. l is a view in perspective of a type of radiator adapted to bemanufactured by my improved method;

Fig. 2 is a horizontal cross-sectional view of a radiator as it lies onits side before it is subjected to bonding operation;

Fig. 3 is an enlarged cross-sectional view taken along the line 3.--3 ofFig. 2;

Fig. 4 is a view, somewhat similar to Fig. 3, showing the bondingmaterial as it is being distributed between the joints of the structure;and

Fig. 5 is a view showing the joints in their completed stage.

In practicing this method a radiator or heat transfer element may beassembled very easily land the bonding material may be distributedeffectively and without material loss during the bonding operation.

A radiator made in accordance with this method may include a pluralityof ns I which have formed therein a plurality of integral projections IIby any suitable forming method. Preferably the fins I0 are made from asingle strip of material in which projections II are formed at properintervals and thereafter the strip is cut in proper length to form thefins I0. The ns I0 are stacked with the projections Il in nestingrelation as shown in Fig. 2, the4 fins being pressed together slightlyto form a fairly tight joint between the nested portions of theprojections. Preferably the projections II are cone-shaped; but any formof projection may be made in which is adapted to nest within theadjacent projection. If desired suitable header constructions are placedat the ends of the longitudinal tubes I2 formed by the nestedprojections II. In the structure shown, these headers are formed at oneend of the radiator by providing stampings I3 from which cones orprojections I4 have been formed and the edge of which has been flangedaround a cup I as indicated at I5a. At the other end of the 'radiatorthe headers are formed from the stamping I8 in which the cones orprojections I 'l are directed inwardly into the header instead ofoutwardly. The edge of the stamping I6 is bent around the edge of thecup I8 as indicated at I8. In the construction shown in the drawings,the headers form a sinuous passageway with the tubes I2; but it is to beunderstood that any connections may be used with the tubes I2, so thateither individual fluids may be fed to the tubes I2, or a single fluidmay be fed through the tubes in series and/or parallel relationship.

Suitable automatic distribution of bonding material to the spaced jointsis provided. Thus strips 20 of bondng material are inserted into thetubes I2 before the radiator structure is closed up by the headers, andif desired the strips 20 may be made long enough so that the endsthereof extend into the headers to provide bonding material for theheaders. As an alternative, a slight amount of bonding material may beprovided for the headers separately from the strips 20.

After the radiator has been assembled as heretofore described the sameis placed in a horizontal position and is subjected to heat, as by beingintroduced into a brazing furnace in which a reducing atmosphere, suchas hydrogen, is maintained. Preferably the radiators are laid on theirsides on the usual conveyor which carries the radiators through thefurnace, and the radiators remain on their sides throughout the heatingoperation, thus being maintained with the same portions of the tubes I2in their lower position as they are carried by the conveyor. No turningof the radiators is necessary. While they radiator travels through theheating zone, the bonding material is melted and the right amount isautomatically distributed to each transverse joint, because the bondingmaterial melts and flows down and is pocketed at the lowest uncoveredpoint 2I of each projection against the end of the projection telescopedtherein. As the bonding material melts wasteful coating of the interiorof the projections II is prevented by maintaining the same portion ofthe tube lowermost, and the bonding material after flowing down by theshortest path to the joint flows by capillary attraction upwardly alongthe transverse joint, as shown at 22 in Fig. 4, and outwardly betweenthe two telescoped projections as indicated at 23, this actioncontinuing all the way around the circumference of the joint until acompletely bonded joint is produced, as indi cated in Fig. 5, the.material owing outthrough the joint to the outside of the tube asindicated at 24. Complete rings of bonding material, extendingunbrokenly from the interior to the exterior of the tube are thusformed. The portions Il are very thin coatings .of the bonding materialwhich are irregularly distributed near the edges of the Joints duringthe capillary now of the bonding material. Thus as the radiator travelsthrough the braxing furnace, the joining material adheres to the innerfaces of the cone projections at the telescoped portions and to theadjacent outer faces of-the projections telescoped therein so that theseams are tightly closed and are fluid-tight. Some of the bondingmaterial drops from the strips intothe headers and also distributes bycapillary attraction all the way upwardly and around the seams I la andIl and forms tight joints there also.

The radiator is cooled suillciently to prevent oxidation while still inthe reducing atmosphere. After the brazing, if desired, the radiator maybe painted, galvanized, or coated with any protective material desired.

This method may be used to make radiators of sheet metal, such as sheetsteel, which has a relatively low coemcient of conductivity,approximately between 0.10 and 0.11 and any bonding material which hassumcient ailinity for the sheet material may be used. When sheet steelis used. the strips 20 may be made of pure copper. which has arelatively high coeillcient of conductivity, approximately such as 0.92which is over eight times that of sheet steel, and such bonding material may take the formof pure copper wires, although any form of stripsmay be used which are capable of automatically distributing the bondingmaterial while melting.

This method is also applicable in the manufacture of tubing, whether asingle tube is made or whether a plurality of parallel tubes, fastenedtogether, are made. The same method may be used in manufacturing asingle tube, with or without ilns, by aligning loops of the ferrousmaterial, inserting the bonding material into the tube, and passing thetube through the heating zone, while maintaining the same portions ofthe tube lowermost, in the same manner as described in the manufactureof the composite tube or radiator.

The term "radiator" `is used herein i'n a generic sense and is intendedto include heat transfer devices in which the heat tlows either from orto the fluid within the tubes. Y While the form of embodiment of theinvention as herein disclosed, constitutes a preferred form, it is to beunderstood that other forms might be adopted, all coming within thescope of the claim which follows.

What is claimed is as follows:

'I'he method of increasing the conductivity of a manufactured heatexchange tube structure and of decreasing the cost of its manufacturingequipment and the cost of its manufacture, which comprises aligning andtelescoping tubular projections of relatively low cost, low heatconducting sheet steel ilns to form a tube having a series of alignedJoints, distributing a relatively small quantity of relatively highcost, high heat conducting cuprous material, having many times higherheat conducting power than said sheet steel, along the bottom andinterior of said tube structure, heating said tube structure in areducing atmosphere, maintaining the tube structure in a substantiallyhorizontal position while being heated and maintaining, while beingheated, the same portion of said tube structure in the lowermostposition to prevent wasteful coating of the projections between saidaligned joints, to guide and proportionally distribute said bondingmaterial to said joints and to cause said bonding material to form aseries of rings of relatively high heat conductivity extendingcontinuously from the interior to the exterior of said tubes.

JOHN KARMAZIN.

